GB2034580A

GB2034580A - Connecting wiper arm to wiper blade assembly

Info

Publication number: GB2034580A
Application number: GB7938056A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1978-11-04
Filing date: 1979-11-02
Publication date: 1980-06-11
Also published as: FR2440850B1; GB2034580B; ES485666A1; FR2440850A1; IT7926910A0; IT1124832B; DE2847953A1

Abstract

A wiper arm (21) having a free U-shaped bent end is pivotally secured to a wiper blade assembly by a resilient clip (22) which is articulated to a pivot pin spanning the sides of a yoke of the wiper blade assembly. The limbs 28, 30 of the clip abut against the mutually facing, substantially parallel surfaces of the bent free end of the wiper arm. Although the width 70 between portions 60 of the clip is greater than the width 66 which is equivalent to the width between the sides of the yoke of wiper blade assembly, it is possible to insert the clip between the sides of the yoke because of its resilience. This avoids lateral play between clip and yoke. <IMAGE>

Description

SPECIFICATION Wiper for screens of motor vehicles The invention relates to screen wipers for motor vehicles.

In order to secure the wiper blade assembly to the wiper arm in a known screen wiper, the wiper arm is inserted between side cheeks of the wiper blade assembly, e.g. between side cheeks of a wiper yoke or harness which supports a wiper blade proper, transversely of the longitudinal axis of the wiper blade, and, when it is in this position, the U-shaped end of the wiper arm is engaged with a hairpinshaped spring. The wiper blade is than pivoted about a pivot pin into its operating position in which the wiper blade and the wiper arm lie substantially in the same plane. During operation of the wiper, the joint between the wiper arm and the wiper blade is subjected to considerable stress, since guidance of the relatively long wiper blade has to be undertaken by the joint of very small dimensions.Thus, it is advisable for the joint to have a minimum of play in order that it can fulfil all of the demands made on it and can withstand the high stresses which occur during operation. When manufacturing the parts, dimensional interference fits can occurwhen endeavouring to eliminate the lateral play between the side cheeks of the wiper blade and the latch spring, the latch spring being wider than the inside width between the two side cheeks. Dimensional mis-fits of this kind can only be avoided by relatively close manufacturing tolerances, although this leads to a considerable increase in the cost of the wiper. Thus, when dimensional misfitofths kind exists, the latch spring cannot enter between the side cheeks of the wiper blade when the blade when the latter is being put into its position for operation.On the contrary, one limb of the spring rests on the top edges of the side cheeks and the two limbs of the spring are pressed together, thus leading to disengagement between the wiper arm and the latch spring and thus to disengagement between the wiper arm and the wiper blade, thus impairing the operational reliability of the wiper.

A wiper for screens of motor vehicles comprises, according to the present invention, a driven wiper arm which is mounted at one end and whose other, free end is U-shaped, a wiper blade pivotally secured to the wiper arm by means of a pivot pin which extends between two spaced side cheeks of the wiper blade transversely of the latter, and which is embraced by the U-shaped end of the wiper arm, and a substantially hairpin-shaped latch spring which is located between the side cheeks when in its operating position and is pivoted about the pivot pin to act as a coupling element between the wiper arm and the wiper blade, the limbs of the latch spring being biassed under initial stress against the faces of the free end of the wiper arm which are at least approximately parallel to one another, the latch spring having at least one portion whose overall width is greater than the distance between the side cheeks of the wiper blade, and resiliently being present to render it possible to insert the entire latch spring between the two side cheeks.

This has the advantage that, when in its operating position, the latch spring is always clamped between the side cheeks of the wiper blade. In this matter, lateral play between the latch spring and the wiper blade is reliably avoided, thus ensuring optimum guidance of the wiper blade on the screen to be wiped. By virtue of the fact that the said resilience enable the latch spring to be put into its operating position even when the latch spring is wider than the distance between the two side cheeks, the tolerances in thickness can also lie in a region which enables the wiper to be manufactured in an inexpensive manner.

The invention is further described, by way of example, with reference to the drawings, in which: Figure 1 is a plan view of the central region of a wiper blade having a latch spring arranged between the side cheeks of the wiper blade, Figure 2 is a side elevation of the latch spring of Figure 1, drawn to a larger scale, Figure 3 is a section through the latch spring of Figure 2 taken on the line Ill-Ill of Figure 4, and Figure 4 is a plan view of the latch spring of Figure 2.

Awiper blade assembly 10, only a portion of which is shown in Figure 1, includes a support yoke 12 of U-shaped cross section, an opening 14 being provided in the region of the bridge portion of the yoke. The width of the opening 14 is chosen such that the bridge portion interconnecting the limbs of the U-shaped support yoke is fully removed. Thus, the support yoke 12 of the wiper blade 10 has in the region of the opening 14 only two spaced side cheeks 16 and 18 disposed parallel to one another. A pivot pin 20 is mounted in the two side cheeks 16 and 18 tranversely of the wiper blade 10 and serves to articulate the wiper blade 10 to a driven wiper arm 21, illustrated by dash-dot lines. The free end of the wiper arm 21 is in the form of a hook by means of which the wiper arm embraces the pivot pin 20.A coupling element 22 is articulated to the pivot pin 20 of the wiper blade 10 in order to ensure satisfactory connection between the wiper arm 21 and the wiper blade 10. The wiper arm is releasably secured to the coupling element 22 which is further illustrated in Figures 2 and 4. The coupling element has a sleeve-like bearing part 24 having a bore 26 for receiving the pivot pin 20. Two substantially parallel limbs 28 and 30 are arranged on the bearing point 24 and, together with the bearing part 24, form a hairpin-shaped latch spring (Figure 3). The limb 30 of the coupling element 22 has an angular extension 32 which is arranged such that it forms, together with the outer wall of the limb 30, a passage 34 for receiving the free extrimity of the hook-shaped end of the wiper arm 21.The two end faces of one limb 30 of the coupling element 22 are connected to walls 36 and 38 which bound the passage 24 laterally. The walls 36 and 38 form lateral boundaries of the latch spring 24, 28, 30 and their distance apart corresponds to the width of the wiper arm 21. The walls 36 and 38 are provided with an open-edged recess 40 in the end region of the limb 28, so that the end region of the limb 28 is laterally exposed. The coupling element 22 is made from a resilient plastics material, and the end region 42 of the limb 28 forms an acute angle with the limb 30.Thus, overcoming a specific spring force, the end region 42 can be deflected upon insertion of the coupling element 22 into the hook-shaped end of the wiper arm 21, such that the end region 42 lies in line with that portion of the limb 28 which is connected to the bearing balt 24. An outwardly directed lug 44 thereby engages an opening in the wiper arm 21 and the outer surfaces 46 and 48 of the limbs 28 and 30 abut with stress against the mutually facing surfaces of the free end of the wiper arm. The two walls 36 and 38 are interconnected by means of a bridge portion 50 at a distance from the resiliently movable end region 42 of the limb 28, the outer surface 52 of which bridge portion also abuts against the wiper arm Figure 3).

The bridge portion 50 forms a rigid extension of the spring limb 28. In order to release the latch lug 44 from the opening in the wiper arm 21,the resilient end region 42 of the limb 28 is provided with grips 54 whose overall width is greater than that of the walls 36 and 38. Upon deflection of the resilient end region 42, the grips 54 enter the recesses 40 in the walls 36 and 38. In order to ensure deflection of the resilient end region 42 with out rubing this end portion is narrower than the wiper arm in so far as the end portion is still located between the walls 36 and 38.

This can be seen particularly in Figure 4 where that portion of the end region 42 which is located between the walls 36 and 38 is cut free from the walls 36 and 38 by means of slot-like undercuts 56.

In order to reduce the friction between the mutuallyfacing surfacesofthesixdecheeks 16 and 18 and those faces of the walls 36 and 38 which face the aforesaid surfaces, the walls are provided with arcuate slide ribs 58 arranged concentrically of the bore 26. At the extreme ends 37 and 39 of the coupling element 22 which are remote from the bearing part 24, that surface of each wall which faces the side cheeks 16 and 18 respectively has a thickened portion 60 which is higher than the slide ribs 58. Each thickened portion 60 is also in the form of an arcuate rib which extends concentrically of the bore 26. These extreme end portions 37 and 39 are not connected to the bridge portion 50.Open-edged slots 62 are disposed in the bridge portion 50 at the mutually facing inner faces of the walls 36 and 38, so that the extreme end portions of the walls 36 and 38 are resiliently deflectable in the direction of the arrows 64. The width 66 of the coupling element 22 measured across the slide ribs 58, is matched to the distance 68 between the side cheeks 16 and 18. On the other hand, the width 70 of the coupling element 22, measured across the thickened portions 60, is wider than the distance 68 between the two side cheeks 16 and 18.

When the coupling element 22 has been pivoted into its operating position together with the wiper arm connected thereto, the rib-like thickened por tions 60 of the coupling element are first seated on the upper edges of the side cheeks 16 and 18.

However, by virtue of the open-edged slots 62, the end portions 37 and 39 form spring means which can compensate for this excess dimension. Namely, the extreme end portions of the walls 36 and 38, on which are disposed the thickened portions 60, can be deflected inwardly in the direction of the arrows 64 to the extent that the thickened portions of these extreme end portions are also positioned between the side cheeks 16 and 18 of the support yoke 12.

When in the operating position then reached, the thickened portions 60 are applied under initial stress to the mutually facing surfaces of the side cheeks 16 and 18, so that the coupling element 22 is mounted on the pivot pin 20 in the opening 14 in the support yoke 12 without any lateral play. To ensure that this inward deflection is also possible when the wiper arm 21 abuts against the mutually facing surfaces of the walls 36 and 38, the distance 72 between projections 74 on the walls 36 and 38 is greater than the distance between the mutually facing surfaces of the walls 36,38 and the other regions of the coupling element 22.

To ensure that the thickened portions 60 of the walls 36 and 38 can enter between the side cheek 16 and 18 of the support yoke 12 without difficulty, it is also possible for the cheeks 16 and 18 to be of resilient construction such that the side cheeks are of slightly spread apart upon introducing the coupling element 22, so that the coupling element can enter between the two side cheeks.

Thus, the extreme free end portions 38 and 39 of the walls 36 and 38 form resilient means which render it possible to insert the latch springs 24,28, 30, provided in the coupling element 22, between the two side cheeks 16 and 18 of the wiper blade yoke 12. The resilient construction of the side cheeks 16 and 18 also forms resilient means for this purpose, and particularly together with the extreme, free end portions 37 and 39 of the walls, facilitates the introduction of the couping element 22 between the side cheeks 16 and 18.

Claims

1. A wiper for screens of motor vehicles, comprising a driven wiper arm whicn is mounted at one end and whose other, free end is U-shaped, a wiper blade pivotally secured to the wiper arm by means of a pivot pin which extends between two spaced side cheeks of the wiper blade transversely of the latter, and which is embraced by the U-shaped end of the wiper arm, and a substantially hair-pin-shaped latch spring which is located between the side cheeks when in its operating position and is pivoted about the pivot pin to act as a coupling element between the wiper arm and the wiper blade, the limbs of the latch spring being biassed under initial stress against the faces of the free end of the wiper arm which are at least approximately parallel to one another, the latch spring having at least one portion whose overall width is greater than the distance between the side cheeks of the wiper blade, and resilience being present to render it possible to insert the entire latch spring between the two side cheeks.

2. A wiper as claimed in claim 1, in which the resilience is achieved at least partially by the side cheeks of the wiper blade being of resilient construc tion.

3. A wiper as claimed in claim 1 or 2, in which the resilience is achieved at least partially by that portion of the coupling element which is wider than the distance between the side cheeks being resilient.

4. A wiper as claimed in claim 3, in which there is a respective wall is disposed at each of the mutually oppositely located sides of one spring limb and such walls are located between the side cheeks of the wiper blade when the wiper is in its operating position, and in which an end region of the coupling element, which is remote from the pivot pin, is at least in part of greater overall width than the distance between the side cheeks of the wiper blade in relation to a resilient end region of the one spring limb.

5. Awiper as claimed in claim 4, in which the latch spring is made from a resilient plastics material, and in which at least one wall has, at its end remote from the pivot pin, a thickened portion which projects towards the adjacent side cheek, and a recess is provided in the region of the thickened portion between that wall and the one spring limb.

6. A wiper as claimed in claim 5, in which the thickened portion of the wall is in the form of an arcuate rib which extends concentrically of the pivot pin.

7. A wiper as claimed in claim 5 or 6, in which each of the walls has a thickened portion and the corresponding recesses are of open-edged and slot-like configuration.

8. A wiper for screens of motor vehicles constructed substantially as herein described with reference to and illustrated in the drawings.